58 research outputs found
Root reinforcement dynamics in subalpine spruce forests following timber harvest: A case study in Canton Schwyz, Switzerland
Root reinforcement is a key factor when dealing with slope stability problems and is an important quantitative criterion for the evaluation of the protective function of forests against shallow landslides, as well as for the adoption of appropriate practices in protection forest management. Although many models have been developed to estimate root reinforcement, a reliable quantification that considers both its spatial and temporal variability still remains a challenge. This work aims to extend the understanding of the long term spatial and temporal dynamics of root reinforcement after forest harvest in subalpine spruce forests by supplying new experimental data and applying a state-of-the-art model.We estimated root reinforcement decay 5, 10 and 15 years after timber had been harvested in spruce stands in a small catchment in the Swiss Alps. We collected root distribution data at different distances from the trees and calibrated and validated a root distribution model (RootDis). To estimate root mechanical properties, we tested roots up to 12 mm diameter in the field, and computed root reinforcement for each case study with the Root Bundle Model. Finally, we developed a new model for the estimation of root reinforcement decay, based on the observed change in root distribution after felling and on the decay of the root pullout force. The final result is a model for the spatial-temporal prediction of root reinforcement heterogeneity and dynamics in subalpine spruce forest stands. Five year old harvested spruce forest in the climatic conditions of the study area provides 40% of the root reinforcement of live forest, while 15 years old harvested forest provides no reinforcement at all. Shrub species and natural regeneration could guarantee almost the 30% of the root reinforcement of a live forest after 15 years from cutting. Additional work is now required to further validate the model and implement these results in a slope stability analysis
Guideline Application in Real world: multi-Institutional Based survey of Adjuvant and first-Line pancreatic Ductal adenocarcinoma treatment in Italy. Primary analysis of the GARIBALDI survey
Background: Information about the adherence to scientific societies guidelines in the ‘real-world’ therapeutic management of oncological patients are lacking. This multicenter, prospective survey was aimed to improve the knowledge relative to 2017-2018 recommendations of the Italian Association of Medical Oncology (AIOM). Patients and methods: Treatment-naive adult patients with pancreatic adenocarcinoma were enrolled. Group A received adjuvant therapy, group B received primary chemotherapy, and group C had metastatic disease. The results on patients accrued until 31 October 2019 with a mature follow-up were presented. Results: Since July 2017, 833 eligible patients of 923 (90%) were enrolled in 44 Italian centers. The median age was 69 years (range 36-89 years; 24% >75 years); 48% were female; 93% had Eastern Cooperative Oncology Group (ECOG) performance status (PS) score of 0 or 1; group A: 16%, group B: 30%; group C: 54%; 72% Nord, 13% Center, 15% South. In group A, guidelines adherence was 68% [95% confidence interval (CI) 59% to 76%]; 53% of patients received gemcitabine and 15% gemcitabine + capecitabine; median CA19.9 was 29 (range 0-7300; not reported 15%); median survival was 36.4 months (95% CI 27.5-47.3 months). In group B, guidelines adherence was 96% (95% CI 92% to 98%); 55% of patients received nab-paclitaxel + gemcitabine, 27% FOLFIRINOX, 12% gemcitabine, and 3% clinical trial; median CA19.9 was 337 (range 0-20220; not reported 9%); median survival was 18.1 months (95% CI 15.6-19.9 months). In group C, guidelines adherence was 96% (95% CI 94% to 98%); 71% of patients received nab-paclitaxel + gemcitabine, 16% gemcitabine, 8% FOLFIRINOX, and 4% clinical trial; liver and lung metastases were reported in 76% and 23% of patients, respectively; median CA19.9 value was 760 (range 0-1374500; not reported 9%); median survival was 10.0 months (95% CI 9.1-11.1 months). Conclusions: The GARIBALDI survey shows a very high rate of adherence to guidelines and survival outcome in line with the literature. CA19.9 testing should be enhanced; nutritional and psychological counseling represent an unmet need. Enrollment to assess adherence to updated AIOM guidelines is ongoing
The effect of chestnut coppice forests abandon on slope stability : a case study
Sweet chestnut has been fundamental for Italian mountainous economies for many centuries. This kind of forest
was traditionally managed by coppicing in shortly rotation (15-20 years) to rapidly produce wood biomass until
half of XX century. In the last decades these forests were in large part abandoned due to change in economy which
made coppiced forest management unprofitable, especially in steeper slopes and where forest viability is scarce.
As a consequence most of them are over aged and very dense, leading to an observed increasing in localized slope
instability, primary because of the uprooting of stools (Vogt et al., 2006).
In this work the effect of the abandon of chestnut coppice on slope stability was analyzed, focusing on shallow
landslides triggering. The mechanical contribution to soil shear strength of differently managed chestnut stand was
estimated and compared in terms of additional root cohesion.
The study area is located in the Valcuvia Valley (Lombardy Prealps - Northern Italy) at an elevation about 600 m
a.s.l., where two different stands, one managed and the other abandoned (over 40 year aged), were chosen. The
two sampling stands are on cohesionless slopes (quaternary moraine deposits) and are homogeneous with regard to
the substrate, exposure and elevation. Slope steepness influences heavily forestry practices and steeper stands are
more frequently abandoned than stands on gentler terrain: in fact in the abandoned coppice the slope was higher
(35 degrees against 13 in the managed stand) and no stands completely homogeneous can be found.
In each site the main characteristics of the stand were surveyed and a trench in each stand was excavated to
analyze root diameter and number distribution with depth; root specimens were also collected for the tensile force
determination through laboratory tensile tests. Root distribution and force were then used to estimate root cohesion
values through a Fiber Boundle Model (Pollen and Simon, 2005).
Results, as expected, show that management didn\u2019t affect root mechanical properties, whereas root distribution
within the soil profile did. In terms of additional root cohesion, values are higher in the managed stand, and lower
in the abandoned one, at least in the first 50 cm of soil. In the abandoned stand, in fact, roots reach deeper layers
of soil (100 cm) than the managed one (50 cm), mainly because of an unexpected greater soil depth.
To assess the implication of such results in terms of slope stability, a simple infinite slope model was applied to
the two conditions. The results showed that the abandoned stand is prone to instability also with a low level of
saturation. On the contrary, by applying the additional root cohesion profile obtained in the managed stand to the
steeper slopes, stability should be guaranteed, except in the case of total saturation.
In conclusion, although more investigations are required especially to extend the number of stands, coppicing
practice seem to be fundamental to prevent shallow landsliding in sweet chestnut forests over cohesionless slopes
The effect of gap openings on soil reinforcement in two conifer stands in northern Italy
Gap-oriented forestry is a subject that is gaining interest worldwide as a compromise between economic and operational requirements on the one hand and environmental and safety concerns on the other. In principle, the approach mimics the effects of fine-scale natural disturbance while avoiding the threats of soil degradation and instability associated with large clearcuts, but at the same time, it does not limit the productivity associated with single-tree selection.
Despite this interest, studies of the real effects of gap-oriented forestry are still limited, particularly those dealing with its impact on slope stability. This paper provides quantitative results about the slope stability of two mixed-conifer stands subjected to gap management in the Italian Central Alps that were monitored for five years after felling.
The results showed that root decay, both in strength and density, further reduces additional root cohesion by approximately 60% in the first two years after felling and by another 20% in the third year; it completely vanishes by the fifth year. The observed reduction in root reinforcement values has dramatic consequences for slope stability. In fact:
- In undisturbed conditions, the contribution of forest root systems guarantees a very low probability of instability (approximately 10% for a factor of safety of less than 1 as well as for steep slopes and high levels of saturation).
- After only two years, the probability of instability dramatically increases for gentle slopes and low levels of saturation. We estimated a 50% probability of a factor of safety less than 1 when steepness was greater than 36-38 degrees and soil saturation was 25% and when steepness was greater than 24-26 degrees and soil saturation was 75%.
- The probability of instability is highest five years after felling when the contribution of the root system has vanished. The probability of failure exceeded 50% when steepness was greater than 25-28 degrees and saturation was 25%, and the slopes were practically unstable when saturation was 75%.
- At the point when the contribution of the root system to slope stability was null, the regeneration process was still too undeveloped to contribute to soil reinforcement in any way.
These results suggest that although the gap-oriented approach is, in principle, more conservative than large clearcuts, the pace of natural regeneration could be slower than the process of root decay, so instability could occur, especially where local slopes exceed 25 degrees and soils are frequently saturated
The contribution of chestnut coppice forests on slope stability in abandoned territory : a case study
Sweet chestnut has been for many centuries fundamental for the Italian mountainous economies, where this kind of forest was traditionally managed in short rotation to rapidly produce wood biomass. Due to the social and economic changes, which made such management scheme unprofitable especially on the steep and remote slopes, such practice has been mainly abandoned and most of chestnut forests became over-aged and very dense, causing an increase of localized slope instability.
In this work the effect of over-aged chestnut coppice forests on shallow landslides was analysed by evaluating and comparing mechanical contribution to soil shear strength provided by root systems in differently managed chestnut stands.
The study area is located in Valcuvia (Lombardy Prealps) where three different stands, one managed and the others abandoned (over 40 year aged), established on cohesionless slopes (quaternary moraine deposits) were chosen having care to select homogeneous conditions in terms of substrate, aspect and elevation. As slope steepness strongly affects forestry practices and steeper stands are more frequently abandoned, the considered stands have different terrain inclination, 30-35\ub0 in abandoned stands and 13\ub0 in the managed one.
Slope stability of the three sites was evaluated by applying the infinite slope approach accounting for additional root cohesion and tree surcharge. Additional root cohesion was estimated through the Fiber Boundle Model approach by collecting roots in the field and measuring their resistance in laboratory, and by measuring root diameter and density distribution with depth by the wall technique method.
The results, as expected, showed that over-aging does not affect root mechanical properties, whereas it significantly affects root distribution within the soil. In terms of slope stability, when steepness exceeds 35\ub0, instability phenomena can be triggered by high level of soil saturation in the case of over-aged forests, whereas for less extreme cases chestnut forests, although over-aged, are able and fundamental to guarantee safe conditions
Renal Cell Carcinoma: the Oncologist Asks, Can PSMA PET/CT Answer?
To critically review the potential clinical applications of prostate-specific membrane antigen (PSMA) radioactive ligands in renal cell carcinoma (RCC).
Radioactive probes targeting PSMA hold promise in several malignancies in addition to prostate cancer, owing to the expression of PSMA by tumor neovasculature. The majority of clear cell RCCs (ccRCC), the most malignant RCC subtype, express PSMA on tumor-associated neovasculature. The endothelium of less aggressive RCC subtypes is PSMA positive in a lower, but still significant percentage of cases. PSMA might therefore represent an interesting theragnostic target in RCC. The preliminary data available suggest a potential role for PSMA-targeting radiopharmaceuticals in complementing conventional imaging for staging ccRCC patients at risk of nodal involvement and oligometastatic disease. Additional applications of PSMA imaging may be the selection and the response assessment of patients receiving anti-angiogenic treatments. The effectiveness of PSMA-targeting radionuclide therapy should also be investigated
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